Spatiotemporal evolution and driving factors of urban–rural integration in the Jinan metropolitan area

Research on the spatiotemporal evolution of urban–rural integration areas within metropolitan regions has received increasing attention with the growing availability of remote sensing data and spatial analytical methods. However, existing studies often rely on single data sources or static frameworks, limiting their ability to capture the dynamic evolution and spatial heterogeneity of urban–rural integration. Based on National Polar-Orbiting Partnership (NPP)/Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime light data from 2017 to 2023, this study develops an integrated framework combining nighttime light threshold segmentation, an improved gravity model, and spatiotemporally weighted geographic regression (GTWR) to identify urban–rural integration areas and examine their spatiotemporal evolution and driving mechanisms in the Jinan Metropolitan Area. The main findings are as follows: (1) Urban–rural integration areas expanded significantly from 2017 to 2023, with fragmented patches evolving into a more continuous spatial pattern, particularly toward the northeast and east. (2) The spatial association pattern showed dynamic shifts in dominant centers between Licheng–Lixia and Taishan–Daiyue, while remaining relatively stable overall and exhibiting increased association intensity. (3) Spatial interaction intensity was concentrated in a few core districts, whereas the socioeconomic locational index showed pronounced spatial differentiation, with declining trends in central areas and increases in peripheral regions. (4) The effects of economic development level, industrial upgrading, fiscal health, the consumer price index, urban land expansion efficiency, and air pollution displayed significant spatial heterogeneity, varying in both magnitude and direction across regions. Compared with existing studies, this research integrates multi-source data and dynamic spatial econometric modeling to capture the identification, evolution, and driving mechanisms of urban–rural integration areas. Overall, urban–rural integration in metropolitan areas is characterized by spatial expansion and strengthening of spatial linkages, providing a replicable framework for targeted policymaking and coordinated regional development.